[pfguo]

Hello to all,

I am confused by empty bracket in the following code:

(symm( L + L.T() ) * eta)(); // L is velocity gradient

Does it mean a function object of the tensor field symm( L + L.T() ) * eta) ?

I didn't find any useful information in the online documentation of OpenFOAM about such usage of tensor field.

I am not sure if function objects for tensor fields are defined in OpenFOAM.

Thanks !



The more complete code is here:

           
          const volVectorField& U = mesh.lookupObject<volVectorField>("U");
          const volScalarField& eta = mesh.lookupObject<volScalarField>("eta");
          
          volTensorField L(fvc::grad(U));
          
          symmTensorField tauP((symm( L + L.T() ) * eta)().boundaryField()[patchi]);